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The X-ray crystallographic structures of methyl 2-O-methyl-α-d -glucopyranoside and methyl 4,6-O-(S)-benzylidene-2-O-methyl-α-d -galactopyranoside
Carbohydrate Research, 241(1993) 261-266 Elsevier Science Publishers B.V., Amsterdam
261
Note
The X-ray c~stallographic structures of methyl 2-O methyl-lx-D-glucopyranoside and methyl 4,6-O-(S)benzylidene-2-O-methyl-a-D-galactopyranoside Patrick McArdle, Desmond Cunningham, Elizabeth Lee and Margaret O’Gara C~e~~t~
repayment,
(Received
November
~~Lle~i~ College, GaZ~ay ~ire~ffd~ 28th, 1991; accepted
August
15th, 1992)
As part of a programme involving X-ray crystallographic studies” of cis- and tpuns-fused hexopyranosides, we now report on the crystal structures of methyl 2-~-methyl-~-D-glucop~anoside* (11, which was obtained by debe~lidenation of methyl 4,~-O-benzyIidene-2-O-methyI-3-O-~-tolylsulfonyl-~-~-glucopyranoside3 followed by detosylation, and methyl 4,6-O-benzylidene-2-0-methyl-cr_D-galactopyranoside (21, which was prepared4 by selective tosylation of methyl 4,6-O-benzylidene-cY-D-galactopyranoside followed by Purdie methylation and detosylation. Perspective views of 1 and 2 are depicted in Figs. 1 and 2, respectively. The final atomic co-ordinates for 1, with their standard deviations in parentheses, are listed in Tables I and II, and the corresponding parameters for 2 are given in Tables III and IV. For 1, the C-C bond lengths in the sugar ring have a mean value of 1.52 A, in agreement with values observed for other carbohydrates, and there is a 4C, conformation with C-2, C-3, C-5, and O-5 coplanar (C-4 and C-l, respectively, lie 0.67 A above and 0.69 A below this plane). There are intermolecular hydrogen bonds involving O-2 and O-4,0-3 and O-6, and O-3 and O-4. The hydrogen atoms attached to O-3, O-4, and O-6 were not located. All other hydrogen atoms were attached in calculated positions with fixed thermal parameters. In the crystal structure of 2, there is the expected5 double-chair conformation with the phenyl group equatorial. For 2, C-5 lies 0.637 A below and C-7 lies 0.66 A above plane 1 (C-6, O-6, C-4, and O-41, and C-4 lies 0.65 A above, and C-l lies 0.69 A below plane 2 (C-2, C-3, C-5, and O-5 of the pyranose ring’. Plane 2 of the pyranose ring lies at an angle of 76.82” to plane 1. The phenyl ring is oriented at an angle of 75.97” to plane 1. There is an intermolecular hydrogen bond involving O-3 and O-6 (2.83 A>. @XX?-6215/93/$06.00
0 2993 - Elsevier Science Publishers
B.V. All rights reserved
P. &Urdle et al. / Curbohydr. Res. 241 (199.3)261-266
Fig. 1. ORTEP” drawing of methyl Z-O-methyla-r~-glucopyranoside (1)and the numbering scheme.
EXPERIMENTAL
Compounds 1 and 2 were prepared as describedZm4. The crystallographic data * are given in Table V. The structures were solved by direct methods, SHELX-RC~~, and refined by full-matrix least squares using SHELX 767. The data were corrected for Lorentz and p&ark&ion effects, but not for absorption, For 1, hydrogen
Fig. 2. ORTEP” drawing of methyl 4,6-U-benzylidene-2-O-methyl-cu-u-galactopyranoside (21 and the numbering scheme.
* ~z~pplern~~~~ material.--Lists of anisotropic and isotropic thermal parameters bond lengths, and bond angles have been deposited with; and can be obtained from, Elsevier Science Publishers, B.V., BBA Data Deposition, P.O. Box 1527, Amsterdam, Netherlands. Reference should be made to No. BBA/DD/519/C’urbohyfZr. Res.. 241 (1993) 261-266.
P. McArdle et al. /Carbohydr. Res. 241 (1993) 261-266
263
TABLE I Fractional atomic co-ordinates for 1 Atom
n
Y
o-1 o-2 o-3 o-4 O-5 O-6 C-l c-2 c-3 c-4 c-5 C-6 c-7 C-8
0.0510 (3) - 0.0263 (3) - 0.0936 (3) -0.1010 (3) -0.1918 (3) - 0.2012 (4) - 0.1062 (4) - 0.1203 (4) - 0.0670 (4) - 0.1563 (4) - 0.1360 (4) - 0.2307 (5) 0.0798 (6) - 0.0834 (5)
-
z 0.6041(3) 0.8195 (2) 0.6869 (2) 0.4052 (2) 0.5050 (2) 0.2264 (2) 0.6264 (3) 0.7050 (3) 0.6206 (3) 0.4913 (3) 0.4194 (3) 0.2927 (3) 0.5470 (5) 0.9226 (4)
-
0.9152 (2) 1.0472 (2) 1.2532 (2) 1.2372 (2) 0.9465 (2) 0.9244 (2) 0.9373 (3) 1.0481(3) 1.1480 (2) 1.1496 (2) 1.0359 (3) 1.0280 (3) 0.8070 (3) 0.9778 (4)
atoms were included in calculated positions with fixed thermal parameters. All atoms were refined anisotropically. For 2, all of the hydrogen atoms were observed in difference maps and were refined with isotropic thermal parameters, except those on the phenyl ring and the OH group which were included in the calculated positions. The oxygen atoms and the carbons of the methyl groups were refined anisotropically. The thermal parameters were terms yj of exp[ - 2rr2(U,,h2a*2 + U22k2b”2 + CJ,,12c*2+ 2U,2hka*b* + 2U,,hla*c* + 2U,klb*c*)l. The atomic scattering factors for non-hydrogen and hydrogen atoms and the anomalous dispersion correction factors for non-hydrogen atoms were taken from
TABLE II Fractional atomic co-ordinates for the hydrogen atoms (1) Atom
x
Y
z
H-l H-2 H-3 H-4 H-5 H-6 H-7 H-8 H-9 H-10 H-11 H-12 H-13
- 0.156 - 0.242 0.057 - 0.278 - 0.013 - 0.353 - 0.199 0.204 0.037 0.021 - 0.005 - 0.198 - 0.092
- 0.682 - 0.733 - 0.603 -0.515 -0.395 - 0.317 - 0.228 - 0.533 -0.612 -0.453 - 1.006 -0.952 - 0.888
-
0.867 1.056 1.138 1.165 1.028 1.033 1.098 0.796 0.742 0.801 0.982 1.007 0.891
P. McArdle et al./Carbohydr.
264
TABLE
Res. 241 (1993) 261-266
III
Fractional
atomic co-ordinates
(8) for 2
Atom
x
Y
z
O-1 o-2 O-3 o-4 O-5 O-h C-8 c-o
0.1648 (5) 0.0618 (5, 0.3757 (5) 0.0263 (4) - 0.0963 (5) -0.1355 (5) 0.1098 (11) - 0.1824 (9) - 0.0521 (7) - 0.2251 (73) 0.0185 (7) - 0.1350 (80) 0.2814 (7) 0.4323 (95) 0.2341 (7) 0.3985 (97) 0.1409 (7) 0.3046 (95) 0.0547 (8) 0.2120 (95) - 0.0495 (86) ~ 0.0242 (7) 0.1649 (83) - 0.0397 (96) 0.1193 (92) 0.275 I (87) -0.2386 (96) - 0.3403 (88) -0.1028 (69) - 0.235 1 (7) - 0.3646 (S) - 0.5588 (9) - 0.6223 (IO) - 0.4965 (9) - 0.3032 (8)
- 0.2485 (2) - 0.0349 (2) - 0.0254 (2) -0.1605 (1) - 0.2907 (2) - 0.3268 (2) - 0.3424 (3) 0.0185 (3) - 0.2181 (2) - 0.2186 (23) -0.1106 (2) - 0.0846 (24) -0.1205 (2) - 0.1484 (26) -0.1998 (2) - 0.2088 (31) - 0.3031 (2) -0.3338 (31) - 0.3764 (3) - 0.3960 (31) - 0.4329 (29) -0.2314 (2) - 0.2471 (25) - 0.3322 (31) - 0.3990 (33) - 0.3594 (34) 0.0629 (3 1) - 0.0325 (30) 0.0619 (58) -0.1874 (2) - O.OY25(3) - 0.0545 (3) -0.1119 (3) - 0.2062 (3) -- 0.2447 (3)
-0.4241(l) -- 0.4068 (1) - 0.3020 (1) - 0.2384 (1) -0.3411 (1) -0.2153 (1) - 0.4552 (2) - 0.4228 (2) -0.3873 (1) - 0.4080 ( 12) -0.3620 (1) - 0.3343 (13) - 0.3358 (1) - 0.3582 (16) - 0.2783 (1) -0.2ShI (16) - 0.3036 (1) -0.3248 (17) - 0.2550 (2) - 0.2270 (15) - 0.2726 (14) -0.1931 (1) -0.1750(13) -0.4816 (17) -- (I.4244 (19) -0.4871 (20) -0.3914 (17) -0.4296 (17) - 0.4548 (28) --0.1514(l) -0.1610(l) -0.1207 (2) ~ 0.0721 (2) - 0.0627 (2) -0.1013 (1)
C-l H-l c-2 H-S c-3 H-10 c-4 H-l I C-5 H-20 C-6 H-18 H-19 C-7 II-12 H-2 H-3 H-4 H-6 H-7 H-8 C-IO C-l I c-14 C-l c-14 C-15
TABLE Fractional Atom H-9 H-13 H-14 H-15 H-16 H-17
IV atomic co-ordinates x
-
0.311 0.322 0.646 0.754 0.543 0.216
(.&) for hydrogen
atoms (calculated
positions)
(2)
Y
I
0.034 -0.053 0.011 - 0.086 - 0.246 -0.310
-0.318 -0.195 - 0.127 - 0.045 - 0.029 - 0.094
P. McArdle et al. / Carbohydr. Res. 241 (1993) 261-266
265
TABLE V Crystal data for 1 and 2
Crystal size (mm) Formula M (amu) Orthorhombic Space group a (A)
1
2
0.3 x 0.21 x 0.38
0.31 x 0.24 x 0.30
Wl6O6
C15H2006
208.211
296.319
P&2*2, 8.554 (2)
p21212, 4.826 (1)
b (A)
10.087 (2)
12.834 (2)
c (A)
11.780 (2)
22.862 (5)
u (A3.3, Z 0, (g.cm-3) CL(cm-‘) FOOO Radiation MO-Ka
1016.33 4 1.36 0.76 448.0
1416.03 4 1.39 0.66 632
Graphite monochromator Diffractometer Orienting reflections range Temperature (“C) Scan methud Data collection range No. of unique data Total I > 3uI No. of parameters fitted Ra, R; Largest shift/esd, final cycle
A = 0.71069 A Enraf-Nonius CAD4F 25,13 < 0 < 20” 22 O-28 2 < 28 < 50” 1370 1210 129 5.0%, 5.13% < 0.001
h = 0.71069 A Enraf-Nonius CAD4F 25,13 < e < 20” 22 w-28 2<20<48” 1768 1573 184 5.12%, 5.91% < 0.001
Largest positive peak (e/i3)
0.16
0.21
Largest negative peak (e/A3)
- 0.07
- 0.09
a R = [B /IF, I - I F, Ill/8 I F, I. bR, = [[Zw( I F, - F, l)2]/[Hw( I F, l)2]]‘/2; w = l/[(oFJ2
0.00031. F:] for 1; w = l/[(aF,)’
0.00015.
Fz] for 2.
the literature’-“. All calculations were performed on a VAX 8700 computer. The ORTEP program” was used to obtain the drawings.
REFERENCES
For example, D. Cunningham, N. Gavin, E. Lee, P. McArdle, J. O’Callaghan, and T. Higgins, Carbohydr. Res., 177 (1988) l-11; E. Lee, P. McArlde, N. Melody, D. Cunningham, and J. Gallagher, ibid., 208 (1990) 231-240; E. Lee, N. Melody, P. McArdle, and D. Cunningham, ibid., 226 (1992) 175-178. W.N. Haworth, E.L. Hirst, and E.G. Teece, J. Chem. Sot., (1931) 2858-2860. S. Umezawa, T. Tsuchiya, and H. Hineno, Bull. Chem. Sot. Jpn., 43 (1970) 1212-1218, and references therein. E. Sorkin and T. Reichstein, Helu. Chim. Acta, 28 (1945) 1-17. N. Baggett, J.M. Duxbury, A.B. Foster, and J.M. Webber, Carbohydr. Res., 1 (1965) 22-30.
266
P. McArdle et al. / Carhohydr. Res. 241 (1993) 261-266
6 G.M. Sheldrick, SHELX86, A Computer Program for Crystal Structure Determination, University of Giittingen, 1986. 7 G.M. Sheldrick, SHELX76, A Computer Program for Crystal Structure Determination, University of Cambridge, 1976. 8 D.T. Cromer and J.B. Mann, Acta Crystallogr., SXL A, 24 (1968) 321-326. 9 R.F. Stewart, E.R. Davidson, and W.T. Simpson, .I Chum Phys., 42 (1965) 317553178. 10 D.T. Cromer and D.J. Liberman, J. Chem. fhys., 53 (1970) 1891-1893. 11 C.K. Johnson, ORTEP. Report ORNL-3794, Oak Ridge National Laboratory, TN. USA, 1965.
261
Note
The X-ray c~stallographic structures of methyl 2-O methyl-lx-D-glucopyranoside and methyl 4,6-O-(S)benzylidene-2-O-methyl-a-D-galactopyranoside Patrick McArdle, Desmond Cunningham, Elizabeth Lee and Margaret O’Gara C~e~~t~
repayment,
(Received
November
~~Lle~i~ College, GaZ~ay ~ire~ffd~ 28th, 1991; accepted
August
15th, 1992)
As part of a programme involving X-ray crystallographic studies” of cis- and tpuns-fused hexopyranosides, we now report on the crystal structures of methyl 2-~-methyl-~-D-glucop~anoside* (11, which was obtained by debe~lidenation of methyl 4,~-O-benzyIidene-2-O-methyI-3-O-~-tolylsulfonyl-~-~-glucopyranoside3 followed by detosylation, and methyl 4,6-O-benzylidene-2-0-methyl-cr_D-galactopyranoside (21, which was prepared4 by selective tosylation of methyl 4,6-O-benzylidene-cY-D-galactopyranoside followed by Purdie methylation and detosylation. Perspective views of 1 and 2 are depicted in Figs. 1 and 2, respectively. The final atomic co-ordinates for 1, with their standard deviations in parentheses, are listed in Tables I and II, and the corresponding parameters for 2 are given in Tables III and IV. For 1, the C-C bond lengths in the sugar ring have a mean value of 1.52 A, in agreement with values observed for other carbohydrates, and there is a 4C, conformation with C-2, C-3, C-5, and O-5 coplanar (C-4 and C-l, respectively, lie 0.67 A above and 0.69 A below this plane). There are intermolecular hydrogen bonds involving O-2 and O-4,0-3 and O-6, and O-3 and O-4. The hydrogen atoms attached to O-3, O-4, and O-6 were not located. All other hydrogen atoms were attached in calculated positions with fixed thermal parameters. In the crystal structure of 2, there is the expected5 double-chair conformation with the phenyl group equatorial. For 2, C-5 lies 0.637 A below and C-7 lies 0.66 A above plane 1 (C-6, O-6, C-4, and O-41, and C-4 lies 0.65 A above, and C-l lies 0.69 A below plane 2 (C-2, C-3, C-5, and O-5 of the pyranose ring’. Plane 2 of the pyranose ring lies at an angle of 76.82” to plane 1. The phenyl ring is oriented at an angle of 75.97” to plane 1. There is an intermolecular hydrogen bond involving O-3 and O-6 (2.83 A>. @XX?-6215/93/$06.00
0 2993 - Elsevier Science Publishers
B.V. All rights reserved
P. &Urdle et al. / Curbohydr. Res. 241 (199.3)261-266
Fig. 1. ORTEP” drawing of methyl Z-O-methyla-r~-glucopyranoside (1)and the numbering scheme.
EXPERIMENTAL
Compounds 1 and 2 were prepared as describedZm4. The crystallographic data * are given in Table V. The structures were solved by direct methods, SHELX-RC~~, and refined by full-matrix least squares using SHELX 767. The data were corrected for Lorentz and p&ark&ion effects, but not for absorption, For 1, hydrogen
Fig. 2. ORTEP” drawing of methyl 4,6-U-benzylidene-2-O-methyl-cu-u-galactopyranoside (21 and the numbering scheme.
* ~z~pplern~~~~ material.--Lists of anisotropic and isotropic thermal parameters bond lengths, and bond angles have been deposited with; and can be obtained from, Elsevier Science Publishers, B.V., BBA Data Deposition, P.O. Box 1527, Amsterdam, Netherlands. Reference should be made to No. BBA/DD/519/C’urbohyfZr. Res.. 241 (1993) 261-266.
P. McArdle et al. /Carbohydr. Res. 241 (1993) 261-266
263
TABLE I Fractional atomic co-ordinates for 1 Atom
n
Y
o-1 o-2 o-3 o-4 O-5 O-6 C-l c-2 c-3 c-4 c-5 C-6 c-7 C-8
0.0510 (3) - 0.0263 (3) - 0.0936 (3) -0.1010 (3) -0.1918 (3) - 0.2012 (4) - 0.1062 (4) - 0.1203 (4) - 0.0670 (4) - 0.1563 (4) - 0.1360 (4) - 0.2307 (5) 0.0798 (6) - 0.0834 (5)
-
z 0.6041(3) 0.8195 (2) 0.6869 (2) 0.4052 (2) 0.5050 (2) 0.2264 (2) 0.6264 (3) 0.7050 (3) 0.6206 (3) 0.4913 (3) 0.4194 (3) 0.2927 (3) 0.5470 (5) 0.9226 (4)
-
0.9152 (2) 1.0472 (2) 1.2532 (2) 1.2372 (2) 0.9465 (2) 0.9244 (2) 0.9373 (3) 1.0481(3) 1.1480 (2) 1.1496 (2) 1.0359 (3) 1.0280 (3) 0.8070 (3) 0.9778 (4)
atoms were included in calculated positions with fixed thermal parameters. All atoms were refined anisotropically. For 2, all of the hydrogen atoms were observed in difference maps and were refined with isotropic thermal parameters, except those on the phenyl ring and the OH group which were included in the calculated positions. The oxygen atoms and the carbons of the methyl groups were refined anisotropically. The thermal parameters were terms yj of exp[ - 2rr2(U,,h2a*2 + U22k2b”2 + CJ,,12c*2+ 2U,2hka*b* + 2U,,hla*c* + 2U,klb*c*)l. The atomic scattering factors for non-hydrogen and hydrogen atoms and the anomalous dispersion correction factors for non-hydrogen atoms were taken from
TABLE II Fractional atomic co-ordinates for the hydrogen atoms (1) Atom
x
Y
z
H-l H-2 H-3 H-4 H-5 H-6 H-7 H-8 H-9 H-10 H-11 H-12 H-13
- 0.156 - 0.242 0.057 - 0.278 - 0.013 - 0.353 - 0.199 0.204 0.037 0.021 - 0.005 - 0.198 - 0.092
- 0.682 - 0.733 - 0.603 -0.515 -0.395 - 0.317 - 0.228 - 0.533 -0.612 -0.453 - 1.006 -0.952 - 0.888
-
0.867 1.056 1.138 1.165 1.028 1.033 1.098 0.796 0.742 0.801 0.982 1.007 0.891
P. McArdle et al./Carbohydr.
264
TABLE
Res. 241 (1993) 261-266
III
Fractional
atomic co-ordinates
(8) for 2
Atom
x
Y
z
O-1 o-2 O-3 o-4 O-5 O-h C-8 c-o
0.1648 (5) 0.0618 (5, 0.3757 (5) 0.0263 (4) - 0.0963 (5) -0.1355 (5) 0.1098 (11) - 0.1824 (9) - 0.0521 (7) - 0.2251 (73) 0.0185 (7) - 0.1350 (80) 0.2814 (7) 0.4323 (95) 0.2341 (7) 0.3985 (97) 0.1409 (7) 0.3046 (95) 0.0547 (8) 0.2120 (95) - 0.0495 (86) ~ 0.0242 (7) 0.1649 (83) - 0.0397 (96) 0.1193 (92) 0.275 I (87) -0.2386 (96) - 0.3403 (88) -0.1028 (69) - 0.235 1 (7) - 0.3646 (S) - 0.5588 (9) - 0.6223 (IO) - 0.4965 (9) - 0.3032 (8)
- 0.2485 (2) - 0.0349 (2) - 0.0254 (2) -0.1605 (1) - 0.2907 (2) - 0.3268 (2) - 0.3424 (3) 0.0185 (3) - 0.2181 (2) - 0.2186 (23) -0.1106 (2) - 0.0846 (24) -0.1205 (2) - 0.1484 (26) -0.1998 (2) - 0.2088 (31) - 0.3031 (2) -0.3338 (31) - 0.3764 (3) - 0.3960 (31) - 0.4329 (29) -0.2314 (2) - 0.2471 (25) - 0.3322 (31) - 0.3990 (33) - 0.3594 (34) 0.0629 (3 1) - 0.0325 (30) 0.0619 (58) -0.1874 (2) - O.OY25(3) - 0.0545 (3) -0.1119 (3) - 0.2062 (3) -- 0.2447 (3)
-0.4241(l) -- 0.4068 (1) - 0.3020 (1) - 0.2384 (1) -0.3411 (1) -0.2153 (1) - 0.4552 (2) - 0.4228 (2) -0.3873 (1) - 0.4080 ( 12) -0.3620 (1) - 0.3343 (13) - 0.3358 (1) - 0.3582 (16) - 0.2783 (1) -0.2ShI (16) - 0.3036 (1) -0.3248 (17) - 0.2550 (2) - 0.2270 (15) - 0.2726 (14) -0.1931 (1) -0.1750(13) -0.4816 (17) -- (I.4244 (19) -0.4871 (20) -0.3914 (17) -0.4296 (17) - 0.4548 (28) --0.1514(l) -0.1610(l) -0.1207 (2) ~ 0.0721 (2) - 0.0627 (2) -0.1013 (1)
C-l H-l c-2 H-S c-3 H-10 c-4 H-l I C-5 H-20 C-6 H-18 H-19 C-7 II-12 H-2 H-3 H-4 H-6 H-7 H-8 C-IO C-l I c-14 C-l c-14 C-15
TABLE Fractional Atom H-9 H-13 H-14 H-15 H-16 H-17
IV atomic co-ordinates x
-
0.311 0.322 0.646 0.754 0.543 0.216
(.&) for hydrogen
atoms (calculated
positions)
(2)
Y
I
0.034 -0.053 0.011 - 0.086 - 0.246 -0.310
-0.318 -0.195 - 0.127 - 0.045 - 0.029 - 0.094
P. McArdle et al. / Carbohydr. Res. 241 (1993) 261-266
265
TABLE V Crystal data for 1 and 2
Crystal size (mm) Formula M (amu) Orthorhombic Space group a (A)
1
2
0.3 x 0.21 x 0.38
0.31 x 0.24 x 0.30
Wl6O6
C15H2006
208.211
296.319
P&2*2, 8.554 (2)
p21212, 4.826 (1)
b (A)
10.087 (2)
12.834 (2)
c (A)
11.780 (2)
22.862 (5)
u (A3.3, Z 0, (g.cm-3) CL(cm-‘) FOOO Radiation MO-Ka
1016.33 4 1.36 0.76 448.0
1416.03 4 1.39 0.66 632
Graphite monochromator Diffractometer Orienting reflections range Temperature (“C) Scan methud Data collection range No. of unique data Total I > 3uI No. of parameters fitted Ra, R; Largest shift/esd, final cycle
A = 0.71069 A Enraf-Nonius CAD4F 25,13 < 0 < 20” 22 O-28 2 < 28 < 50” 1370 1210 129 5.0%, 5.13% < 0.001
h = 0.71069 A Enraf-Nonius CAD4F 25,13 < e < 20” 22 w-28 2<20<48” 1768 1573 184 5.12%, 5.91% < 0.001
Largest positive peak (e/i3)
0.16
0.21
Largest negative peak (e/A3)
- 0.07
- 0.09
a R = [B /IF, I - I F, Ill/8 I F, I. bR, = [[Zw( I F, - F, l)2]/[Hw( I F, l)2]]‘/2; w = l/[(oFJ2
0.00031. F:] for 1; w = l/[(aF,)’
0.00015.
Fz] for 2.
the literature’-“. All calculations were performed on a VAX 8700 computer. The ORTEP program” was used to obtain the drawings.
REFERENCES
For example, D. Cunningham, N. Gavin, E. Lee, P. McArdle, J. O’Callaghan, and T. Higgins, Carbohydr. Res., 177 (1988) l-11; E. Lee, P. McArlde, N. Melody, D. Cunningham, and J. Gallagher, ibid., 208 (1990) 231-240; E. Lee, N. Melody, P. McArdle, and D. Cunningham, ibid., 226 (1992) 175-178. W.N. Haworth, E.L. Hirst, and E.G. Teece, J. Chem. Sot., (1931) 2858-2860. S. Umezawa, T. Tsuchiya, and H. Hineno, Bull. Chem. Sot. Jpn., 43 (1970) 1212-1218, and references therein. E. Sorkin and T. Reichstein, Helu. Chim. Acta, 28 (1945) 1-17. N. Baggett, J.M. Duxbury, A.B. Foster, and J.M. Webber, Carbohydr. Res., 1 (1965) 22-30.
266
P. McArdle et al. / Carhohydr. Res. 241 (1993) 261-266
6 G.M. Sheldrick, SHELX86, A Computer Program for Crystal Structure Determination, University of Giittingen, 1986. 7 G.M. Sheldrick, SHELX76, A Computer Program for Crystal Structure Determination, University of Cambridge, 1976. 8 D.T. Cromer and J.B. Mann, Acta Crystallogr., SXL A, 24 (1968) 321-326. 9 R.F. Stewart, E.R. Davidson, and W.T. Simpson, .I Chum Phys., 42 (1965) 317553178. 10 D.T. Cromer and D.J. Liberman, J. Chem. fhys., 53 (1970) 1891-1893. 11 C.K. Johnson, ORTEP. Report ORNL-3794, Oak Ridge National Laboratory, TN. USA, 1965.